Disease control syringe having a retractable needle

Abstract

A disposable disease control syringe which reduces the frequency of accidental needle strikes to health care workers and prevents health-threatening reuse of the needle cannula by drug abusers. The syringe includes a cylinder having an open proximal end, a substantially closed distal end, and a retractable needle projecting through the distal end. A piston assembly having a detachable stem and a needle capturing receptacle moves axially and distally through the syringe cylinder to expulse fluid medication and to selectively engage the needle at the most distal aspect of the cylinder. The piston assembly is then withdrawn proximally through the cylinder, whereby to relocate the needle from the distal end to the proximal cylinder end. The needle capturing receptacle is locked at the proximal end of the syringe cylinder with the needle cannula retracted within and completely shielded by the cylinder. The stem is then detached from the piston assembly and discarded, thereby creating a disposal cartridge with the needle cannula rendered permanently irretrievable therewithin. Alternatively, the piston assembly can be driven distally through the cylinder for correspondingly moving the needle into contact with a puncture resistant shield located at the distal end of the cylinder, whereby the needle is axially collapsed and destroyed within the cylinder.

Having thus set forth a preferred embodiment of the invention, what is claimed is: 
     
       1. A syringe comprising a hollow cylinder having a substantially closed distal end and an open proximal end and a needle extending through said distal end and communicating with the interior of said cylinder, said syringe further comprising: means movable axially and reciprocally through said cylinder for engaging said needle at the distal aspect of said cylinder and for relocating said needle from the distal end of said cylinder to a relatively proximal position within said cylinder; and   means located at the distal aspect of said cylinder to cooperate with said axially and reciprocally movable means for destroying said needle at the interior of said cylinder.   
     
     
       2. The syringe recited in claim 1, wherein said means for destroying said needle comprises a needle puncture resistant shield located adjacent the distal end of said cylinder at the interior thereof, said needle being moved axially and distally through said cylinder and into contact with said shield for axially collapsing and, thereby, destroying, said needle. 
     
     
       3. The syringe recited in claim 2, wherein said needle puncture resistant shield includes a plurality of concentrically aligned annular ribs, said needle being moved into contact with said shield between a pair of said ribs. 
     
     
       4. The syringe recited in claim 1, wherein said means movable axially and reciprocally through said cylinder for relocating said needle is a piston. 
     
     
       5. The syringe recited in claim 4, wherein said needle has a distal cutting end which projects outwardly from said cylinder and a needle catch formed at a proximal end and spaced inwardly from the distal end of said cylinder, said piston engaging said needle catch at the distal aspect of said cylinder for relocating said needle to the relatively proximal position within said cylinder. 
     
     
       6. The syringe recited in claim 5, wherein said piston has a needle capturing receptacle formed at one end thereof for selectively engaging the needle catch at the proximal end of said needle. 
     
     
       7. The syringe recited in claim 6, wherein said needle capturing receptacle is formed between a plurality of flexible legs, each of said legs terminating at an inwardly projecting lip, said needle catch being received within said receptacle and below the respective lips of said legs to prevent the withdrawal of said needle catch from said receptacle after said needle catch has been received therewithin. 
     
     
       8. The syringe recited in claim 7, wherein at least one of said flexible legs is longer than other ones of said legs, such that said needle is canted relative to the longitudinal axis of said cylinder when said needle catch is received within said needle capturing receptacle and said needle is relocated from the distal end to a relatively proximal position within said cylinder. 
     
     
       9. A syringe comprising a hollow cylinder having a substantially closed distal end and an open proximal end and a retractable needle extending through said distal end and communicating with the interior of said cylinder, said syringe further comprising: a piston movable axially and reciprocally through said cylinder for engaging said needle at the distal aspect of said cylinder and for relocating said needle from the distal end to a relatively proximal position within said cylinder, said piston having means for canting said needle relative to the longitudinal axis of said cylinder when said needle is engaged by said piston and moved to said relatively proximal position within said cylinder; and   means for destroying said canted needle at the interior of said cylinder when said needle is moved by said piston into contact therewith.   
     
     
       10. The syringe recited in claim 9, wherein said means for destroying said canted needle comprises a needle puncture resistant shield located at the distal end of said cylinder, said needle being moved by said piston axially and distally through said cylinder and into contact with said needle destroying shield to axially collapse, and thereby destroy, said needle. 
     
     
       11. The syringe recited in claim 10, wherein said puncture resistant shield includes a plurality of concentrically aligned annular ribs, said needle being moved into contact with said shield between a pair of said ribs. 
     
     
       12. The syringe recited in claim 9, wherein said piston means for canting said needle includes a hollow needle capturing receptacle formed at one end of said piston for selectively engaging said needle at the distal end of said cylinder and for aligning said needle at an angle relative to the longitudinal axis of said cylinder when said needle is relocated from said distal end to the relatively proximal position within said cylinder. 
     
     
       13. The syringe recited in claim 12, wherein said needle capturing receptacle is formed between a plurality of flexible legs, at least one of said legs being longer than other ones of said legs, such that said needle is canted when received within said needle capturing receptacle and relocated to the relatively proximal position within said cylinder. 
     
     
       14. A syringe comprising a hollow cylinder having proximal and distal ends and a needle extending through said distal end and communicating with the interior of said cylinder, said syringe further comprising: means movable axially and reciprocally through said cylinder for engaging said needle and relocating said needle from said distal end to a relatively proximal within said cylinder; and   needle puncture resistant means located at the distal end of said cylinder to collapse and thereby destroy said needle at the interior of said cylinder when said needle is advanced distally through said cylinder from said relatively proximal position therewithin.   
     
     
       15. The syringe recited in claim 14, wherein said needle puncture resistant means is a shield located at the distal end of said cylinder, said needle being moved axially and distally through said cylinder and into contact with said shield for collapsing and thereby destroying said needle at the interior of said cylinder. 
     
     
       16. The syringe recited in claim 14, wherein said means for engaging and relocating said needle is a piston. 
     
     
       17. The syringe recited in claim 16, wherein said piston includes means for canting said needle relative to the longitudinal axis of said cylinder, such that said needle is aligned at an angle with respect to said longitudinal axis when said needle is advanced distally through said cylinder from said relatively proximal position therewithin.